British Journot of Pkic 0
Surgery ( 1992). 45, 302-306
1992 The British Association of Plastic Surgeons
Free rectus abdominis muscle reconstruction of the anterior skull base A. Yamada, K. Harii, K. Ueda and H. Asato Department of Plastic Surgery, Faculty of Medicine, The University of Tokyo, Tokyo, Japan SUMMARY. Pericranial flaps and galeal frontalis myofascial flaps can be useful for separating the cranial space from the paranasal sinuses and the nasopharynx, but they cannot provide reliable separation and protection of the brain from bacterial flora of the upper airway in patients who previously have received high dose radiation therapy and undergone craniotomy, or required extensive resection of the cranial base. The free rectus abdominis muscle flap, on the other hand, can provide a good alternative for reconstruction of the anterior skull base in such difIicult cases, and give good results. In six cases using free rectus abdominis flaps, there have been neither cerebrospinal fluid leaks nor meningitis. There was one flap failure due to venous congestion.
adjacent to the dura or the dural graft overlying the frontal lobe. The upper half of the rectus abdominis muscle and anterior rectus sheath is harvested through a paramedian abdominal incision. When a facial skin defect requires reconstruction, a free musculocutaneous flap can be harvested. The deep inferior epigastric vessels can be detached from the posterior surface of the rectus abdominis muscle to form a pedicle about 12-15 cm long. A cranial bone graft, if required, is applied to the orbital roof but not to the cribriform plate and lamina papyracea. The defect in the anterior cranial fossa communicating with the frontal, ethmoid and sphenoid sinuses is then packed with the free rectus abdominis muscle. The internal surface of the muscle within the nasopharynx is supported by the anterior rectus sheath or a fascia lata graft sutured to the nasal mucosal margins at the orbital floor level. The deep inferior epigastric vessels are passed through either a subcutaneous tunnel in the cheek to be anastomosed with the facial vessels, or through a burr hole in the lateral wall of the frontal bone to join the superficial temporal vessels (Fig. 1).
Advances in craniofacial surgical techniques have made extensive combined craniofacial resections possible producing good and curative results, especially in the case of patients whose turnours, located in the anterior cranial base, were previously considered to be unresectable. However, infection may be a major problem because of the close proximity of the paranasal sinuses and nasopharynx to the intracranial contents. Immediate and adequate reconstruction is therefore required to shield the dura and extradural space from the paranasal sinuses and the nasopharynx and avoid subsequent cerebrospinal leakage, meningitis and extradural abscesses resulting from secondary contamination. Although recently introduced local tissue flaps such as pericranial flaps (Johns et al., 1981) and galeal frontalis myofascial flaps (Jackson et al., 1986) can be useful in separating the intracranial cavity from the paranasal sinuses and nasopharynx, they may be insufficiently bulky to provide separation and protection of the brain from bacterial flora of the upper airway in patients who have previously received high dose radiation therapy and undergone craniotomy, or required extensive resection of the cranial base. The free rectus abdominis muscle flap, on the other hand, can provide a good alternative for reconstruction of the anterior skull base in such difficult cases.
Results Between 1987 and 1991, seven patients aged from 22-50 years underwent anterior skull base reconstruction with nine free rectus abdominis muscle flaps. Two patients underwent reconstruction twice because of tumour recurrence. Two patients had chondrosarcomas, two meningiomas, 1 chordoma, 1 squamous cell carcinoma and 1 olfactory neuroblastoma. Five patients had undergone previous craniotomy, and four had received more than 50 Gy irradiation. All patients underwent single-stage resection of the extracranial and intracranial tumour, followed by immediate reconstruction. The muscle pedicle of 7 of the 9 flaps used was anastomosed to the facial vessels and
Operative technique In the case of tumours extending both intracranially and extracranially, a combined intra- and extracranial approach is required. The intracranial tumour is excised and, if required, dural repair performed intracranially with pericranium, fascia lata or anterior rectus sheath grafts while the extracranial tumour is excised through a lateral rhinotomy. The defect resulting from the resection of these tumours usually consists of an opening in the nasopharynx immediately 302
Free Rectus Abdominis Muscle Reconstruction
of the Anterior Skull Base
subcutaneous tunnel in the cheek to be anastomosed with the facial vessels. The surface of the muscle within the nasopharynx fascia lay against a graft at the orbital floor level (Fig. 2B). The patient did well postoperatively. Five months later, there was a recurrence of the tumour in the right orbit and ethmoid and maxillary sinuses. The tumour was excised again intra- and extracranially and the defect in the anterior cranial base, ethmoid sinuses and right orbit packed with another rectus abdominis muscle flap, with anastomoses to the superficial temporal vessels (Fig. 2D). The surface of the muscle within the nasopharynx was again supported by the fascia lata graft (Fig. 2C). There was no cerebrospinal fluid leakage or meningitis. The patient has been followed up for 1 year since the secondary reconstruction, and there has been no evidence of local recurrence. Case 2
Fig. 1 Figure l-Schematic outline. (Above) Black area represents the anterior skull base defect. (Below) Dural graft (d), vascularised
A 36-year-old man had undergone partial maxillectomy through lateral rhinotomy for olfactory neuroblastoma and underwent radiotherapy three times (total 162 Gy) and chemotherapy twice over a period of 1.5 years. A tumour recurred at the anterior cranial base. The tumour was excised intra- and extracranially by a neurosurgical and ENT team. The dural defect under the frontal lobe was repaired with the anterior rectus sheath and the defect of the cribriform plate, ethmoid and sphenoid sinuses, and both laminae papyraceae (Fig. 3A) was packed with the rectus abdominis muscle (Fig. 3B). The surface of the muscle within the nasopharynx was supported by the anterior rectus sheath at the orbital floor level (Fig. 3C). The vascular pedicle of the grafted muscle was passed through a subcutaneous tunnel in the cheek to reach the facial vessels. There was no cerebrospinal fluid leakage or meningitis, and radiation therapy began at 2 postoperative weeks.
rectus abdominis muscle (m), fascial support (0. Case 3
that of the other 2 flaps to the superficial temporal vessels. Calvarial bone grafts were used for reconstruction of the orbital roof in two cases. There was only one instance of cribriform plate reconstruction in 8 reconstructions of the skull base. There was neither cerebrospinal fluid leakage nor meningitis in 6 cases in which 8 flaps were used. In one case, however, there was failure of the free rectus abdominis muscle flap because of venous congestion, and the patient died of rupture of the internal carotid artery in the first postoperative month. The remaining six patients are alive and well.
excision of an ethmoidal chondrosarcoma and underwent radiotherapy twice (total 116 Gy) and chemotherapy once over a 6-year period. The tumour was excised intra- and extracranially. The resultant defect included an opening in the nasopharynx and exposed frontal and ethmoid sinuses, right orbital roof and both laminae papyraceae. The orbital roof was reconstructed with a calvarial bone graft and the defect was packed with a rectus abdominis muscle. The bone graft was completely covered by the muscle. The postoperative course was uneventful. The patient has now been followed up for 20 months.
After the advent of musculocutaneous flaps, the pectoralis major (Sasaki et al., 1985) and extended trapezius myocutaneous flap (Rosen. 1985) were used for reconstruction of the anterior cranial base. The main disadvantage of the pectoralis major M-C flaps is that a secondary division of the pedicle is frequently required and they have to be extended flaps to reach that far, and are therefore not very safe by comparison with free flaps, In addition, the extended trapezius M-C flap requires repositioning of the patient for flap elevation. The free microsurgical transfer of a latissimus dorsi muscle or musculocutaneous flap (Guelinckx and Lejour, 1986; Guignard er al., 1988) is extremely
A 22-year-old woman had undergone intracranial excision four times of a frontal malignant meningioma and received 50 Gy of radiation over a period of 3 years. There was recurrence of tumour extracranially at the anterior cranial base, and we excised this intra- and extracranially. The frontal lobe was underlaid with a fascia lata graft for dural repair. Following resection the resultant defect consisted of an opening in the nasopharynx and opening into both ethmoid and frontal sinuses, sphenoid sinus, right orbital roof and both laminae papyraceae (Fig. 2A). The right orbital roof was reconstructed with a calvarial bone graft. The defect of the anterior cranial base, ethmoid sinuses and sphenoid sinus was packed with the rectus muscle. The vascular pedicle of the muscle was passed through a
A 22-year-old woman had undergone intracranial
British Journal of Plastic Surgery
Fig. 2 Figure t--Case 1. (A) Resection of tumour reveals open nasopharynx. (B) The free rectus abdominis muscle flap packed into anterior cranial base defect with anastomoses to facial vessels also obliterates open paranasal sinuses. (C) Internal surface of the muscle within the nasopharynx is supported by fascia lata graft. (D) Defect of the anterior cranial base, ethmoid sinuses and right orbit is packed with rectus abdominis muscle, with anastomoses to the superficial temporal vessels.
useful as it provides a large quantity of well vascularised tissue, but it is difficult to harvest it at the same time as the head and neck procedure is going on. The free rectus abdominis muscle flap (Sekhar et al., 1987) has been used to reconstruct defects in the middle and posterior cranial base. 12-l 5 cm of deep inferior epigastric vessels can be detached from the posterior surface of the rectus muscle. This length is sufficient for anastomosis to the facial vessels or superficial temporal vessels. The muscle can be fitted easily into irregular cavities and provides sufficient bulk to prevent CSF leaks. It appears especially well suited for anterior cranial base reconstruction, as well as reconstruction of the middle and posterior cranial base. In addition, the muscle brings in a good blood supply, allows for diffusion of systemic antibiotics to the site of the operation, rapid and uneventful healing of the wound, and early postoperative radiation therapy if required. The rectus abdominis muscle can be elevated without having to reposition the patient. The disadvantages are that microsurgical vascular anastomosis is required, and free muscle flaps buried sub-
cutaneously are not visible for postoperative monitoring. Postoperatively, the vascular inflow of the deep inferior epigastric artery can be checked by using a Doppler probe, but there is no way of checking for venous thrombosis. Snyder-man et al. (1990) in most cases did not find it necessary to reinforce the cranial base with avascular bone grafts. The use of such grafts could actually delay healing by preventing coaptation of the dura and vascular flap. A water-tight dural closure, in conjuction with a pericranial or galeopericranial flap, provides adequate support of the intracranial contents. Sasaki et al. (1985) demonstrated that bone grafts used to support the brain were rarely necessary in pectoralis major myocutaneous flap reconstruction of the anterior skull base. Calvarial bone grafts were used for reconstruction of the orbital roof in two of our cases, but for reconstruction of the cribriform plate in only one of six cases. The laminae papyraceae were removed in five cases, and reconstruction was performed simply by packing with rectus abdominis muscle. There has been no evidence of postoperative brain herniation into the nasal cavity. We conclude that the cribriform
Free Rectus Abdominis
of the Anterior
Fig. 3 Figure 3-Case
2. (A) Defect of cribriform plate, ethmoid and sphenoid sinuses, and both laminae papyraceae. (B) Anterior rectus sheath is
sutured to the nasal mucosal margin at orbital floor level. (C) Ethmoid sinuses packed with rectus abdomims muscle.
plate and laminae papyraceae do not require reconstruction with bone grafts in conjunction with muscle flap reconstruction of the anterior cranial base. Some surgeons might prefer to use a skin graft on the exposed nasal surface of the vascularised flaps (Johns et al., 1981, Price ef al., 1988). In our cases, however, the fascia graft on the surface of the muscle within the nasopharynx has not required skin grafting. The exposed nasal surface becomes epithelialised by the surrounding nasal mucosa within 1 or 2 months
and the possibility of problems with chronic desquamation and nasal hygiene associated with a new graft are lessened (Jones et al., 1986; Snyderman r’r al., 1990). We believe that the free rectus abdominis muscle flap is a good alternative for reconstruction of anterior cranial base defects when local tissue flaps cannot be used because of previous craniotomy and high dose radiation therapy, or when extensive resection of the cranial base is required.
References Guehckx, P. J. and Lejour, M. (1986). Free muscle transplants for chronic infection of the fronto-cranial region. Europeon Journal of Plastic Surgery, 9, 88.
Guignard, R. M., Krupp, S., Savary, M. and Campiche, R. (1988). Team approach of sinuso-orbital tumours invading the skull base. European Journal of Plastic Surgery, 11, 169.
Jackson, I. T., Adham, M. N. and Marsh, W. R. (1986). Use of the galeal frontalis myofascial flap in craniofacial surgery. Plastic and Reconstructive Surgery, 77, 905.
Johns, M. E., Winn, H. R., McLean, W. C. and CantreII, R. W. (1981). Pericranial flap for the closure of defects of craniofacial resections. Laryngoscope, 91,952. Jones, N. F., Sekhar, L. N. and Schramm, V. L. (1986). Free rectus abdominis muscle flap reconstruction of the middle and posterior cranial base. Plastic and Reconstruclive Surgery, 78, 471. Price, J. C., bury, M., Carson, B. and Johns, M. E. (1988). The pericranial flap for reconstruction of anterior skull base defects. Laryngoscope, 98, 1159. Rosen, H. M. (1985). The extended trapezius musculocutaneous flap for crania-orbital facial reconstruction. Plastic and Reconstructive Surgery. 75, 318.
Sasaki, C. T., Ariyan, S., Spencer, D., Buckwalter, J. and Haven, N.
of Plastic Surgery
(1985). Pectoralis myocutaneous reconstruction of the anterior skull base. Laryngoscope, 95, 162. Sekhar, L. N., Schramru, V. L. and Jones, N. F. (1987). Subtemporal-preauricular infratemporal fossa approach to large lateral and posterior cranial base neoplasms. Journal of Neurosurgery, 67, 488.
Snyderman, C. H., Janeeka, I. P., Sekhar, L. N., Sen, C. N. and Eibling, D. E. (1990). Anterior cranial base reconstruction : role of galeal and pericranial flaps. Laryngoscope, 100, 607.
The Authors Atsushi Yamada, MD, Associate Professor. KIyonori HarII, MD, Professor. Kaxuki Ueda, MD, Assistant Professor. Hirotaka Asato, MD, Instructor. Department of Plastic Surgery, Faculty of Medicine, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, Japan. Requests for reprints to Dr. Yamada. Paper received 22 July 1991. Accepted 28 August 1991,after revision.